1. Field of the Invention
The invention relates to a process of preparing a metal salt and to lubricant compositions containing same. More particularly, it is related to a such metal salt made by reacting a hydrocarbon in the presence of a metal oxide, adding an oxidizing gas and then reacting the product thus obtained with a phosphorus sulfide and more metal oxide.
2. Discussion of the Prior Art
It is well known that hydrocarbon lubricating oils tend to oxidize in use in an engine with attendant formation of oxidation products which are acidic in character and which exert a corrosive action on the engine parts, such as the hard metal alloy bearings. Furthermore, it is well known that the gradual deterioration of the oil in use due to oxidation, etc. is attended by formation of carbonaceous sludge and lacquer which adheres to the engine parts, particularly the piston ring grooves and skirts, thereby lowering the efficiency of the engine and frequently causing the rings to stick. To counteract these conditions, the art has developed chemical agents which when added in small amounts to engine lubricating oils have the ability to greatly retard the oxidation of the oil in use. Agents have also been developed which have the ability to prevent deposition of sludge materials on the engine parts, thereby keeping the engine clean and free from the clogging and sticking effects normally encountered. These two types of chemical agents are known in the art as anti-oxidants and detergents, respectively. The present invention provides a new class of chemical products which exhibit both anti-oxidant and detergent properties. U.S. Pat. No. 2,830,949 discloses a class of compounds produced by reacting a hydrocarbon, which has been oxidized in the presence of a metal hydroxide, with a phosphorus sulfide and more metal hydroxide.